1. Field of the Invention
The present invention relates to an electronic device with a touch panel, and more particularly, to an electronic device with an invisible light touch panel, and a light guiding plate of the electronic device can be an indicating button or a light bar for decoration.
2. Description of the Prior Art
A conventional infrared touch panel disposes a plurality of infrared receivers and a plurality of infrared emitters respectively on four sides of a circuit board. The infrared emitters disposed around the circuit board simultaneously generate infrared signals to the opposite infrared receivers, so an infrared network can be formed above a surface of the circuit board. When a user purposes to control the touch panel, the user can utilize an object to slide over the touch panel. The object can be a finger or a stylus. A part of infrared signal is interdicted when the object moves into the infrared network. Because each combination is composed of one infrared emitter and one infrared receiver, the infrared touch panel can distinguish a position of the interdicted infrared signal. Then, a controller can analyze infrared signal variation, and transmit a result to a processor, so that the processor can show position information of the object via the touch panel, or execute the other application programs according to the position information by software.
For completely transmitting the infrared signal outputted from each infrared emitter to the corresponding infrared receiver, a light guide plate of the conventional infrared touch panel covers the whole area on the touch panel. The infrared network formed by the infrared emitters and the infrared receivers also covers the display area on the touch panel completely. The infrared network can detect any interference by the object when the object moves into the infrared network, and can distinguish the position information by digital calculation. Therefore, the light guide plate of the conventional infrared touch panel has huge volume. For example, a tablet computer with the conventional infrared touch panel includes a plurality of indication lights, such as a power light, a button light and a trademark light. Each indication light of the tablet computer is disposed on a lateral surface, or a frame adjacent to the lateral surface of the tablet computer. Difficulty of circuit disposition and mechanical disposition of the conventional infrared touch panel is increased due to the mechanical design constraint of the indication lights.